The near-ultraviolet photoluminescence of ZnO nanorods induced by multiphoton absorption of unamplified Ti:sapphire pulses is investigated. Power dependence measurements have been conducted with an adaptation of the ultrashort pulse characterization method of interferometric frequency-resolved optical gating. These measurements enable the separation of second harmonic and photoluminescence bands due to their distinct coherence properties. A detailed analysis yields fractional power dependence exponents in the range of 3–4, indicating the presence of multiple nonlinear processes. The range in measured exponents is attributed to differences in local field enhancement, which is supported by independent photoluminescence and structural measurements. Simulations based on Keldysh theory suggest contributions by three- and four-photon absorption as well as avalanche ionization in agreement with experimental findings.
Metadata
Item Type:
Article (Published)
Refereed:
Yes
Additional Information:
The authors thank M. Tischer of Max Born Institute (MBI) for the SEM images. J. Tomm, K. Reimann,
M. Wörner, and T. Elsaesser of MBI are thanked for helpful discussions. G. Mangalgiri and B. Heidmann of Helmholtz-Zentrum Berlin are thanked for conducting the X-ray diffraction measurements.
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Funders:
LaserlabEurope (grant number EU-FP7 284464) under project ”Femtosecond field-induced bandgap modification in dielectric materials” (FIBMOD; project ID MBI002096), Australian Institute of Nuclear Science and Engineering (AINSE) award (ALNGRA15541), Science and Industry Endowment Fund (SIEF).
ID Code:
22250
Deposited On:
21 Feb 2018 10:22 by
Enda Mcglynn
. Last Modified 24 Jul 2019 08:54